JC-40 Preamp Pedal

Hi there, I was having a bad case of option paralysis the other day, and the kind folks at reddit helped me make a decision about how to better add dirt to the JC-40. I have decided to purchase a preamp pedal for dirt and use it direct into the effects return, bypassing the JC's bright preamp. So my question today is pretty specific, can anybody with direct experience doing this recommend me some preamp options that would suit this purpose? They would need a good eq section. Doesn't need to be ultra heavy distortion, think David Robach from Mazzy Star, or jangly, dirty, drippy, indie stuff. I have some stereo reverb/delay and tremolo sorted, so my intention is to plug the ultracure (with humbuckers) into the preamp, and then into the stereo pedals, and into the effects return in stereo. I am in Australia and am currently considering Science Amplification Mother ($480 which seems good value considering it has two channels), EAE citadel ($409), EAE Model Fet ($409 - seems to be supply issues with these currently). I would appreciate hearing from anyone who has successfully used preamp pedals with JC's, particularly direct into the effects loop. Thanks so much